Each year, nearly two million tons of liquid ammonia pass through the Port of Tampa on the way to processing plants that manufacture fertilizer used around the world.

Just how dangerous ammonia can be became vividly clear this week, as a fertilizer facility exploded in the city of West, Texas, leveling large parts of the small town. This follows two incidents in the Tampa region in recent years where breaches in ammonia pipelines forced evacuations and killed wildlife nearby.

Meanwhile, ammonia plays a key role in manufacturing fertilizer that boosts crop yields around the world.

After phosphate ore is collected from huge open-pit mines across Florida, it’s brought to chemical processing plants, mixed with sulfuric acid, and then mixed with ammonia to make the material dissolvable in water so farmers can spray it on their fields.

The Port of Tampa handled 1.8 million tons of liquid ammonia in its fiscal year 2012, making it one of the port’s largest products. Much of the ammonia now comes from Trinidad. Anhydrous ammonia isn’t like the household cleaners, which are dissolved in water. It’s naturally a gas that’s cooled and highly pressurized into a liquid.

If released, the fluid vaporizes into a colorless, highly irritating gas with a sharp, suffocating odor. Even small amounts can burn the eyes, nose and throat and breathing even a small amount can be lethal.

Two recent cases in the Tampa region highlight the risks.

In 2007, a teenager in Riverview drilled into a 6-inch pipe that runs 28 miles from Port Sutton to two phosphate plants in Polk County and one in Hillsborough County, apparently because he thought the pipeline carried money between banks. The breach sent the teenager to the hospital, released a cloud of ammonia and forced the evacuation of hundreds of residents near the Alafia River.

In 2003, a man looking for materials to make methamphetamine drugs was arrested after attempting to tap in to a different part of the same pipeline in Lithia. That breach forced the closure of two schools, scorched trees and killed wildlife.

One of the largest users of ammonia is The Mosaic Co., and officials with that company issued a formal statement, saying “Our hearts go out to the people affected by the incident at a West Fertilizer facility in Texas last night.”

So far, they said, it’s premature to draw too many conclusions, or know “if the fertilizer products produced at the facility are the same as our phosphate products.”

Mosaic operates three area fertilizer plants in Riverview, Bartow and on New Wales Road near Mulberry. Mosaic uses pipelines from the port to reach those facilities, said spokeswoman Martha Monfried.

Security around Mosaic facilities has been heightened since Sept. 11, 2001, Monfried said. Emergency teams have drills monthly on company sites, she said, and conduct drills with outside fire rescue departments at least once a year.

Currently, the site in Bartow is shut down for scheduled maintenance and inspection, Monfried said, adding that “everyone is on high alert now.”

The other major ammonia handler at the port is CF Industries, which receives ammonia by tanker ship, and can store up to 38,000 tons of anhydrous ammonia at the port. That facility moves 400,000 tons of ammonia a year, said Richard Ghent, director of community affairs for phosphate operations.

Most of that moves over rail lines, with about 14 rail cars a day moving from the Hooker’s Point terminal, Ghent said, but about 22 trucks a day also leave the facility with ammonia, many of them going through Ybor City on their way to Interstate 4.

CF operates one fertilizer factory just north of Plant City that produces more than two million tons of fertilizer a year, he said.

“There’s a tremendous concern, and empathy any time someone in the business has an accident,” he said. “We’ll all tend to disseminate any lessons so we can get better, and we’ll work hard to do that.”